Clinically overt infection of the placenta, fetal membranes, or uterus during labor (chorioamnionitis) complicates from 1% to 11% of pregnancies. The incidence of uterine infection after delivery (endometritis) varies from 1%-3% after vaginal delivery to 15-20% after cesarean delivery. Chorioamnionitis is a recognized risk factor for bacteremia and septic shock and is associated with a several-fold increase in the risk for cesarean delivery. Women who undergo cesarean delivery in the setting of chorioamnionitis are at increased risk of serious pelvic and wound infection. The most severe complications of endometritis (including, rarely, death from whelming sepsis) usually occur after cesarean delivery. The economic costs of chorioamnionitis and endometritis (collectively referred to as peripartal infection) are substantial and can be conservatively estimated at $120,000,000 a year in the U.S. for post- cesarean infections alone. The offspring of women with chorioamnionitis are exposed to invasive diagnostic testing (e.g. lumbar puncture for cerebrospinal fluid assessment), intravenous antibiotic therapy, prolonged hospitalization, sepsis, and death, Survivors face an increased risk of cerebral palsy. Furthermore, the costs of caring for infants born to mothers with chorioamnionitis may easily exceed the maternal costs of peripartal infection. Because the etiology of chorioaminonitis and endometritis is ascending infection of endogenous cervico-vaginal bacteria, intrapartum irrigation of the vagina and cervix with an anti- bacterial as a logical approach to prevention of peripartal infection. To be clinically useful, such an agent would need to possess broad antimicrobial activity, and be non-toxic and non-irritating for mother and fetus. Ideally the agent would be commercially available and inexpensive. The widely used medical disinfectant chlorhexidine satisfies these requirements. There we aim: 1) To conduct a placebo-controlled, double- masked, randomized clinical trial to determine whether intrapartum vaginal irrigation with a dilute chlorhexidine solution will prevent or lessen the trial to determine whether intrapartum vaginal irrigation with a dilute chlorhexidine solution will prevent or lessen the severity of the maternal peripartal infections--chorioamnionitis and endometritis; 2) To determine whether intrapartum vaginal irrigation with a dilute chlorhexidine solution will reduce the rate of microbial invasion of the chorioamnion; 3) To determine whether intrapartum vaginal irrigation with a dilute chlorhexidine solution will reduce the rate of acute histologic chorioamnionitis; 4) To determine whether the presence of bacterial vaginosis is associated with a differential effect of chlorhexidine vaginal irrigation on the maternal peripartal infection rate; and 5) To determine whether intrapartum vaginal irrigation with a dilute chlorhexidine solution reduces the rates of neonatal sepsis.